One of the most common disorders for which patients request assistance from pharmacists is headache.1
It is critical for pharmacists to have a thorough understanding of
which types of headache can be safely self-treated and which headaches
must be referred to a physician for further evaluation.

Prevalence of Headache

Headache is not a reportable disease, so it is likely
that the available prevalence data underestimate its true occurrence.
The National Institute of Neurological Disorders and Stroke (NINDS)
estimates that fully 90% of adults will experience one or more headaches
during their life, and an appreciable number of these patients will
experience more than one type of headache.2 About two-thirds of children have had a headache of one type or another by the time they reach the age of 15 years.2

Etiology of Headache Pain

Humans have 12 cranial nerves originating at the base of the brain.2
One is the trigeminal nerve, with three branches that innervate the
scalp, intracranial/extracranial vasculature, meninges, face, neck,
ears, eyes, and throat.2 The brain itself is unable to feel
pain, as it lacks pain receptors. However, pain-sensitive nerve endings
(nociceptors) are able to carry pain messages via the trigeminal nerve
to the thalamus in reaction to pain-inducing stimuli. These triggers
include stress, foods, odors, and medications. The thalamus transmits
the pain signals to the brain. When they reach it, the patient perceives
a headache.

Headache Classification

Headache has a very complicated differential diagnosis, because there are at least 150 different types.2
Experts attempt to simplify the diagnostic process by creating various
classification schemes and taxonomies. The NINDS, for instance, assigns
headaches to one of only four broad categories: 1) vascular headache
(e.g., migraine, cluster headache, toxic headache induced by fever,
headache caused by hypertension); 2) tension (muscle contraction)
headache; 3) traction headache; and 4) inflammatory headache.3
The agency explained that the latter two headache types are usually
caused by a more serious underlying disorder, as in the case where
meningitis causes inflammation.

Primary Versus Secondary Headaches

A useful classification for pharmacist consultation is one
that uses just two categories: primary and secondary headaches. Primary
(or benign) headaches are those that are not caused by any serious
underlying disorder, as opposed to the rare secondary headaches induced
by an organic pathology.2 Fortunately, 99% of headaches are primary in origin.4,5 Most primary headaches can be self-treated, while secondary headaches should be referred.

Migraine Headache

Approximately 12% of Americans experience migraine headaches.2 The usual age of onset is 10 to 45 years, and migraine is more common in females.2,6
The causes of migraine pain are not fully elucidated, but the source is
hypothesized to be within the brain, specifically via activation of
nerve fibers located within the walls of certain blood vessels within
the brain that perfuse the meninges. The first physiological abnormality
is thought to be temporary narrowing of some blood vessels, decreasing
the brain’s supply of blood and oxygen. This event is followed by a
compensatory enlargement of other vessels in an attempt to normalize the
brain’s oxygenation.2

Patients may be able to identify factors that trigger
their migraines. Triggers are highly individual, and reportedly include
changes in sleep patterns, missed meals (perhaps resulting in
hypoglycemia), physical stress or exercise, abrupt changes in the
weather or environment, strong odors or chemical fumes, smoking or being
in proximity to smokers, caffeine withdrawal, loud or sudden noise,
motion sickness, emotional stress, depression, anxiety, hangover,
hormonal changes related to the menstrual cycle or pregnancy, and
bright/flashing lights.2,6

Patients may mention that their migraine was preceded by
an aura, which often involves visual abnormalities such as a blind spot,
flashing lights that obstruct vision, zigzag lines moving across the
visual field, eye pain, and/or tunnel vision. The aura may also include
tingling paresthesias in the extremities. Patients describe migraine
pain as a throbbing, pounding, or pulsating ache that is usually
unilateral.6 A dull ache at pain onset usually worsens to
full intensity that may persist for 6 to 48 hours. Ancillary
manifestations reported by patients may include fatigue, photophobia,
phonophobia, nausea or vomiting, sweating, and chills.

Tension Headache

Patients may ask pharmacists about headaches that appear
to have been brought about by tension, stress, or anxiety. This is the
most common type, reflecting the widespread existence of tension and
stress in the lifestyles of many Americans. The cause is thought to be a
reaction to stress, which is to contract the muscles of the neck and
scalp.7 Tension headache is a dull pressure that does not
throb. It may feel as though a tight band or vise is encircling the
head, with the most severe pain in the scalp and temples and possible
involvement of the back of the neck and shoulders. There is no aura, and
tension headaches seldom cause nausea or vomiting.

Cluster Headache

Cluster headache, the most severe type of primary
headache, is a type of trigeminal autonomic cephalgia in which the
patient experiences severe pain in and around one eye.2,8 The
headache may be preceded by an aura and/or nausea. Attacks occur in
clusters in which the patient has headaches almost every day for a
period of weeks to months, followed by a pain-free period before another
closely spaced cluster of attacks begins.

Cluster headache is characterized by a set of
physiological problems on the same side of the face as the pain,
including redness and tearing of the eye, ptosis of the eyelid,
rhinorrhea from one nostril, unilateral nasal congestion, inflammation
under or around the painful eye, and/or redness or flushing of the face.8 The constellation of problems that accompany cluster headache aids the pharmacist in recognizing this type of headache.

Nonprescription Internal Analgesics

Nonprescription internal analgesics carry labeling for
treatment of headache. Pharmacist questioning at the point of sale can
ensure that the patient is treating an appropriate type of primary
headache and that there are no warning signals that would necessitate
referral to a physician. If the pharmacist considers nonprescription
products appropriate, treatment choices include aspirin, acetaminophen
(APAP, e.g., Tylenol), ibuprofen (e.g., Advil, Motrin IB) and naproxen
(e.g., Aleve). The risk of Reye syndrome in children coupled with a long
list of adverse reactions and warnings with aspirin use has sidelined
it as a first-line medication for headache and other minor aches and
pains, but APAP, ibuprofen, and naproxen are useful if the labeled
warnings are followed.

Labeling Issues With Nonprescription Products

Each internal analgesic carries numerous label instructions meant to ensure safe use when they are followed.9-13
Some are age restrictions—ibuprofen in the appropriate dosage form can
be used down to the age of 6 months, but APAP is not safe for
unsupervised use under the age of 2 years, and naproxen is restricted to
those aged ≥12 years. APAP may be used up to any age without
supervision, but ibuprofen and naproxen labels caution patients aged ≥60
years to speak to a physician before use due because of a heightened
risk of gastric bleeding.9-11

Acetaminophen

Acetaminophen carries a prominent set of warnings meant to prevent liver damage.9
Product labeling cautions patients that severe liver damage can occur
if the patient takes more than 4,000 mg of APAP daily, takes the
nonprescription form of APAP with other medications also containing the
drug, or has three or more alcoholic drinks every day while using the
product. APAP labels also warn against unsupervised self-use if the
patient takes warfarin, develops new symptoms, is pregnant or
breastfeeding, has pain that worsens or persists for more than 10 days,
or if erythema or inflammation is present.9

NSAIDs: Ibuprofen and Naproxen

The nonsteroidal anti-inflammatory drugs (NSAIDs)
ibuprofen and naproxen carry a set of warnings meant to prevent stomach
bleeding.10,11 These products warn patients against
unsupervised self-use if the patient is aged ≥60 years, has a history of
stomach ulcers or bleeding problems, is taking an anticoagulant or
corticosteroid, is taking a medication containing any other NSAID, takes
three or more alcoholic drinks every day while using it, or exceeds the
labeled time for self-use. They warn against use if the patient has
ever had an allergic reaction to any other pain reliever or fever
reducer; just before or after heart surgery; or if the patient is
pregnant or breastfeeding. Labels point out the specific risks of use
during the last trimester of pregnancy in order to avoid problems for
the fetus and complications during delivery.10,11

Labels also caution patients to speak with a physician if
the stomach bleeding warnings apply to them; if they have a history of
problems or serious adverse reactions from previous use of pain
relievers or fever reducers; if they have a history of gastric problems
(e.g., heartburn); if they have hypertension, heart disease, hepatic
cirrhosis, renal disease, or asthma; or if they are taking a diuretic.10,11
Labels instruct patients to stop use and speak to a physician if they
experience signs of gastric bleeding (faintness, vomiting of blood,
bloody/black stools, stomach pain that does not improve); if the pain
worsens or persists for more than 10 days; if new symptoms appear; or if
redness or swelling is present in the painful area. Aleve labels also
warn patients to stop use and speak to a physician if they have
difficulty swallowing or it feels as if a tablet is stuck in the throat.11

Migraine-Specific Products

Pharmacists may recommend one of two specific migraine products, Excedrin Migraine and Advil Migraine.12,13
The former contains APAP, aspirin, and caffeine, and the latter
contains ibuprofen. In addition to the precautions listed above, the
labels warn potential purchasers against self-use if they have never had
migraine diagnosed by a physician; if this headache is different from
their usual migraines; if it is the worst headache of their life; if
they have fever or stiff neck; if the headache began after or was caused
by head injury, exertion, coughing, or bending; if they experience
daily headaches; or if the migraine is so severe as to require bed rest.12,13

PATIENT INFORMATION

Which Types of Headache Can I Treat Myself?

There are several types of headache that are not due to
any serious underlying cause, and you may treat them yourself. They
include migraine (diagnosed by a doctor), tension headache, and cluster
headache. If you have not yet obtained a formal diagnosis, your
pharmacist can assist you in deciding whether your headache might belong
to one of these categories.

Furthermore, consult your pharmacist for assistance in
choosing a specific OTC product for your headache. Treatment choices
include acetaminophen (e.g., Tylenol), ibuprofen (e.g., Advil, Motrin
IB), and naproxen (e.g., Aleve). Be sure to carefully read all
directions and precautions on the label of these products, including age
restrictions.

What Is Considered a Dangerous Cause of Headache?

While you can safely self-treat some headaches, there are
times you should see a physician instead. If a blow to the head preceded
the headache, it is mandatory to see a doctor to make sure you do not
have a concussion. If you think your headache might stem from a sinus
infection, an antibiotic prescribed by a physician is the best course of
action. If a temporomandibular joint disorder (TMJ or “clicking jaw”)
might be causing the headache, you may need surgical intervention to
correct the situation.

If you have a persistent, nagging headache at the time of
year when you just turned on the heating in your house or apartment, you
should consider carbon monoxide as a cause. Faulty heating systems
allow this deadly odorless gas to enter your living spaces, causing
headache, nausea, vomiting, dizziness, fatigue, weakness, confusion,
fainting, disorientation, visual problems, and seizures. You must leave
the dwelling immediately and call 911 for transport to an emergency room
if you suspect carbon monoxide exposure.

Alarming Signs

There are other times when you should be sufficiently
alarmed about headache to seek immediate medical care. Is it the first
headache you have ever had? This could mean you have a neurologic
problem. If the headache was brought about by exertion or exercise, it
may be due to an aneurysm (ruptured blood vessel). If you became less
aware of your surroundings or your mental function has changed, a stroke
may have occurred. If the headache is the worst one you have ever had
or is unusually severe, you must seek care for diagnosis of the cause.

If your headache occurred like a “bolt from the blue,”
this might indicate that you have suffered a hemorrhage inside the
skull, which demands immediate attention. If your headache occurred
along with stiff neck, sensitivity to light, nausea, vomiting, and/or
loss of consciousness, you may have meningitis, and this must be
medically treated. Headache with pain around the eye(s) may be due to
glaucoma. If left untreated, glaucoma may cause irreversible loss of
vision, so you must seek immediate care.

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